Optical systems have become increasingly important in modern telecommunications primarily due to their huge information handling capacity. Systems usually include lasers, photodetectors, and modulators, as well as other elements. The speed of such devices has increased to a point where 40 GHz operation will be a standard for the next generation of systems.
One of the problems associated with such high speeds is that transmission line loss increases with frequency. For example, a loss of 1 dB is typical for a 40 GHz modulator with a co-planar waveguide transmission line used for biasing the modulator. It is undesirable to have a loss characteristic which varies with frequency, since such a characteristic tends to distort the optical intensity waveform resulting in possible loss of data. It is desirable, therefore to produce devices with a low and essentially constant loss characteristic as a function of frequency.